Information on QHY cameras.

[RobF (Rob)]

Thanks for the interesting reading all.

I usually put some argon in the body of my 9 a few times each year according to the older linked thread here.

Sometimes every 18months or so may polish the outer CCD chamber very gently. Have used Q tips and isopropanol before, but generally its so clean a puff/brush then gentle breath and polish is sufficient. Can tell from reflections of bright room light if there's anything on there before and after.

Love the 2 stage cooling on my 9.
-25 in the middle of Qld summer (when there are no clouds )

The chamber warming circuit generally works very well, as long as you ramp up the cooling over 10-15 mins. Easy to do with modern software while everything else is getting sorted.

[alpal]

Originally Posted by RobF

Thanks for the interesting reading all.

I usually put some argon in the body of my 9 a few times each year according to the older linked thread here.

Sometimes every 18months or so may polish the outer CCD chamber very gently. Have used Q tips and isopropanol before, but generally its so clean a puff/brush then gentle breath and polish is sufficient. Can tell from reflections of bright room light if there's anything on there before and after.

Love the 2 stage cooling on my 9.
-25 in the middle of Qld summer (when there are no clouds )

The chamber warming circuit generally works very well, as long as you ramp up the cooling over 10-15 mins. Easy to do with modern software while everything else is getting sorted.

Thanks for that info.
Yes - I like my QHY9 m too - it's good value for the price.
Obviously it has a few minor problems but they can all be overcome.

cheers
Allan

[alpal]

Update after the black horizontal line problem:

Using my 8" f6 Newt -
I finally got to do a proper star test after I adjusted the pot in the QHY9 mono.
It's much better - I had to really stretch it with HDR toning to see any black line.
See the pic of Alpha Centauri.

I also did a Ha 20 minute bin 2x2 exposure of the statue of Liberty Nebula
which came out quite well.
I also took a fair bit of LRGB of the same target.
I have a lot of processing to do.

cheers
Allan

[alpal]

Originally Posted by alpal

posted on this thread 21-02-2015, 02:03 PM with pics

I opened up the camera & made the adjustment.
The value of the Pot R27 is 100 ohms.

The info provided by QHY is misleading.
They say 2.2 Volts but their Oscilloscope documents show 2 + .2 of a division
( because they are on 2 Volts per centimeter ) which is actually 2.4 Volts.
When I checked my QHY9 it was 2.4 Volts but the waveform does not look
identical to their picture.
I used 1 volt per centimeter to get more accuracy.
I can't see any ringing on top of the waveform but maybe my CRO doesn't have the bandwidth..

I adjusted it to 2.2 Volts & will test it at the first opportunity
to see if the black horizontal lines on bright stars have gone.

I bought 2 different types of 100 ohm preset pot so that I could install
one of them at an external location but I will see if the above works first.
I added 2 giant photos on flickr of the 2 PCBs - top & bottom.

see pic:

Update 29th January 2017.

The QHY9M horizontal bleed line problem is solved.
I took 2 pics & posted them here on the forum:
http://www.iceinspace.com.au/forum/s...d.php?t=152997


The trick was to adjust the pot R27 here:
https://www.flickr.com/photos/247194...in/photostream
to get the correct waveform &
then only use slow download - about 12 seconds.
Don't tick the box for fast download when in capture mode.
( Actually it says that in the book but it should be in giant letters - I missed it.)

Also - the slow download has far less noise than fast download.
The dark noise on fast download is about 4225 bit count of the maximum 65536 bit count
whereas the dark noise is only about 1029 bit count for slow download.
4000 is about the average sky noise so you get a considerable advantage in signal to noise ratio too.

see the attached pic showing the difference using NASA FITS liberator & centering
the slider in the middle of the noise hump of 2 dark frames
depending on the readout speed.
Left hand side is slow readout speed & Right hand side is fast readout speed.


cheers
Allan